My screen keeps blanking after about 30 seconds of inactivity, but I’ve got that option disabled in settings.
Should also note, this is a desktop computer, without a battery, and is always plugged in.
I have a similar issue caused by the “unblank screen saver” extension, but in my case it is related to plugging/unplugging power which cannot happen in your case if you have a desktop.
However, I’ve invested quite some time to investigate the issue and you can probably reuse some of it to root cause your issue: gsd-power: screen blanking after 30 seconds when laptop plugged to dock while suspended (#866) · Issues · GNOME / gnome-settings-daemon · GitLab
You can first test if the workaround of restarting gsd-power.target helps.
Download the script gsd-blank-bug.sh linked in the report, it will help you configure gsd-power.service to log more information. You probably are victim of a similar issue where gsd-power gets confused and forgets to clear the “blank callback” but we need to understand why in your case.
Please comment on the bug linked above if you investigate, it would help having more reports.